Starch Properties, Nutrients Profiles, In Vitro Ruminal Fermentation and Molecular Structure of Corn Processed in Different Ways

Round 1

Reviewer 1 Report

The manuscript presents the results of the study evaluating how thermal processing affects corn properties compared to ground corn. The authors evaluated starch properties, composition, in vitro ruminal fermentation and molecular structure of the resulting products. Molecular structure was assessed using FTIR molecular spectroscopy.

Firstly, authors should check the manuscript for grammar errors (I found a number of errors such as plural/singular, missing words, sentence formation). Secondly, when comparing results with different studies, authors must remember that the presented results are within the condition of thermal processing they used. In some other conditions, the resulting products could have different properties.

Other concerns are:

Section 2.1. Add model and producer of grinder, steam flaking system and extruder.

L92 Add the commercial name of the kit

L109 and equation Degradation rate refers to the kinetic parameter rate, which was not estimated. Starch degradation rate should be rephrased as starch degradability as it represents total degradability at given timepoint. On the other side, since gas production was monitored during different timepoints (0.5-48h), the authors could estimate the fermentation (degradability) rate from these values.

Figure 1. Add unit on the y axis

Table 1. Remove the dot before parenthesis

Table 4. Add “corn processed in different ways.”

L233-235 Recheck the section – grinding will not improve starch content and explain how more starch hydrolysis in glucose will result in higher starch content.

L238-239 Recheck the conclusion that Maillard reactions could be a reason for decreased protein content. Maillard reactions could reduce protein availability, but the Kjeldahl method was used for determination, and it includes bound protein.

L253 Correct to “reflecting the fermentation extent in the rumen”

L264 Or conditions used during thermal processing

L352-364 Rephrase the paragraph – the relationship between FTIR results and fermentation results is confirmed, but it is too optimistic to say that FTIR results could predict the fermentation extent. They could imply the relationship between analysed products in fermentation characteristics.

L373 Starch release was not measured

 

L372-379 The Conclusion was written as the repetition of the main results. Rewrite this section.

Author Response

Reviewer 1

The manuscript presents the results of the study evaluating how thermal processing affects corn properties compared to ground corn. The authors evaluated starch properties, composition, in vitro ruminal fermentation and molecular structure of the resulting products. Molecular structure was assessed using FTIR molecular spectroscopy.

Firstly, authors should check the manuscript for grammar errors (I found a number of errors such as plural/singular, missing words, sentence formation). ///We went through the manuscript and tried to correct the possible errors.

Secondly, when comparing results with different studies, authors must remember that the presented results are within the condition of thermal processing they used. In some other conditions, the resulting products could have different properties. ///We agree that different thermal processing methods may result in products with different properties. The objective of the current study was to compare the effects of three processing methods, rather than the comparison among different conditions of the same kind of processing technique. Therefore, the related discussion was mainly compared with the similar study (SFC & GC (or untreated corn), EC & GC (or untreated corn), or GC (or untreated corn) & SFC & EC).

Other concerns are:

Section 2.1. Add model and producer of grinder, steam flaking system and extruder. /// Model and producer were added.

L92 Add the commercial name of the kit. /// Starch Content Assay Kit is the commercial name of the kit. The commercial name was used in the first version of manuscript.

L109 and equation Degradation rate refers to the kinetic parameter rate, which was not estimated. Starch degradation rate should be rephrased as starch degradability as it represents total degradability at given timepoint. On the other side, since gas production was monitored during different timepoints (0.5-48h), the authors could estimate the fermentation (degradability) rate from these values./// Starch degradation rate was replaced with starch degradability. In addition, the rate of gas production in every period was calculated and shown in figure 2.

Figure 1. Add unit on the y axis. ///The unit of figure 1 was added.

Table 1. Remove the dot before parenthesis ///The dot was removed.

Table 4. Add “corn processed in different ways.” ///It was added in the title of table 4.

L233-235 Recheck the section – grinding will not improve starch content and explain how more starch hydrolysis in glucose will result in higher starch content. ///Starch was determined by anthrone colorimetry. The measurement principle is to use 80% ethanol to separate the soluble sugar and starch in the sample, then use acid hydrolysis method to decompose starch into glucose. The starch content was calculated by measuring the glucose content. One step in the determination was gelatinization in a boiling water bath for 15 minutes. The gelatinization degree of starch in the process of steam flaking and extruding is greater than that of grinding. This is equivalent to increasing the gelatinization degree in starch determination.

L238-239 Recheck the conclusion that Maillard reactions could be a reason for decreased protein content. Maillard reactions could reduce protein availability, but the Kjeldahl method was used for determination, and it includes bound protein. ///The comments are right. The sentence was deleted.

L253 Correct to “reflecting the fermentation extent in the rumen” ///The more fermentable substances in the feed, the more VFA is produced, and the more gas is produced accordingly. The sentence has not been revised.

 

L264 Or conditions used during thermal processing. ///Some revisions have been made.

L352-364 Rephrase the paragraph – the relationship between FTIR results and fermentation results is confirmed, but it is too optimistic to say that FTIR results could predict the fermentation extent. They could imply the relationship between analysed products in fermentation characteristics. ///As the reviewer pointed out, it is too optimistic. The reason is that the sample is not enough. If there are enough sample and a regression equation based on the data will be obtained, it is possible to draw such a positive conclusion. Some revisions have been made.

L373 Starch release was not measured///Some revisions have been made.

L372-379 The Conclusion was written as the repetition of the main results. Rewrite this section./// This section was rewrote.

 

 

 

Reviewer 2 Report

 

 

Material and methods

it would be adequate to perform a microbiological examination of the collected rumen fluid before and after the different corn addition to the feed. But for this research your examinations were valid

line 76 - more replicates should be concerned to the future research

I had few questions for the authors

Were the prepared corn feeds lately used in animal diets ? 

Have you encountered problems in the feed preparation process? improper grain size? What was the humidity of the input material (corn) ?

Overall, the article is beneficial for practical use and I recommend it for publication.

I wish authors a lot of success in further research 

Author Response

Reviewer 2

Material and methods

it would be adequate to perform a microbiological examination of the collected rumen fluid before and after the different corn addition to the feed. But for this research your examinations were valid

line 76 - more replicates should be concerned to the future research /// Although the three replicates in the design are sufficient for the statistical purposes.  In order to increase the credibility of the results and conclusion, more replicates will be concerned in the future research. 

I had few questions for the authors

Were the prepared corn feeds lately used in animal diets?///Yes.

Have you encountered problems in the feed preparation process? improper grain size? What was the humidity of the input material (corn) ? ///In the following animal experiment, we will design three starter feed (with the ground, steam flaked and extruded corns). The physical form of three starter feeds will be the same pellet. So the grain size and humidity of the experimental feed will be the same.

Overall, the article is beneficial for practical use and I recommend it for publication.

I wish authors a lot of success in further research.///Thank you for your good wishes.

 

Reviewer 3 Report

Dear Authors,

 The paper entitled „Starch properties, nutrients profiles, in vitro ruminal fermentation and molecular structure of corn processed in different ways” focused on comparing the effects of three processing methods of corn: grinding, steam flaking and extruding on the starch properties, nutrient profiles, in vitro ruminal fermentation, and molecular structure. For evaluation the effects of processing methods Authors used vibrational molecular spectroscopy, univariate molecular spectral analysis, and multivariate molecular spectral analyses. The obtained results are interesting from cognitive and practical point of view. Authors found that extruding is the most effective processing method of corn.

 The manuscript is good written, but it needs major revisions as reported in the specific comments.

I propose, basing on the literature, to add some information discuss the question of costs of compared methods of corn processing. This is an important issue for the practical application of these methods in practice.

Table 1. Results are expressed in % DM. I suggest using units that are compatible with the International System of Units that is g kg^-1, not %.

Figure 1. No unit on the Y axis.

Table 3. No unit for presented values.

Table 1 and Figure 2 placed in the wrong place in the text of manuscript.

L211- I suggest moving this sentence to the M&M section.

Author Response

Reviewer 3

Dear Authors,

 The paper entitled „Starch properties, nutrients profiles, in vitro ruminal fermentation and molecular structure of corn processed in different ways” focused on comparing the effects of three processing methods of corn: grinding, steam flaking and extruding on the starch properties, nutrient profiles, in vitro ruminal fermentation, and molecular structure. For evaluation the effects of processing methods Authors used vibrational molecular spectroscopy, univariate molecular spectral analysis, and multivariate molecular spectral analyses. The obtained results are interesting from cognitive and practical point of view. Authors found that extruding is the most effective processing method of corn.

 The manuscript is good written, but it needs major revisions as reported in the specific comments.

I propose, basing on the literature, to add some information discuss the question of costs of compared methods of corn processing. This is an important issue for the practical application of these methods in practice. ///The processing cost of the three corns was the highest for extruded corn, followed by steam-flaked corn, and then the ground corn. We agree that any feed processing technique should be based on cost accounting, rather than just obtaining effects on animal. Few comparative studies of the two thermal processed corn in ruminant animal production (in promoting gastrointestinal development and performance) have not been reported, so it is difficult to make a comparison of cost accounting. And that's what we're going to do next. At present, both processed corns are used in the starter feed of ruminant animal. It is generally used in the feed of young ruminants and not be used during the whole fattening period. We predict a good cost-benefit ratio for the use of two thermal processed corn in ruminant animal production. Some information about this was added in the discussion section.

Table 1. Results are expressed in % DM. I suggest using units that are compatible with the Internation，al System of Units that is g kg^-1, not %./// Correction was done.

Figure 1. No unit on the Y axis. ///Correction was done.

Table 3. No unit for presented values. ///The unit was added.

Table 1 and Figure 2 placed in the wrong place in the text of manuscript. ///Correction was done.

L211- I suggest moving this sentence to the M&M section. ///The sentence was moved to the M&M section.

 

Round 2

Reviewer 1 Report

The quality of the manuscript was improved, but there are several concerns left.

There is still a number of grammar mistakes. For example, the sentence in L36-38 (Previous researches showed that simply mechanical process such as grinding (G) could break the pericarp, reduced the granular size, and endosperm was partially exposed [2], the surface area of rumen enzymes contacted with endosperm is was increased [5] and the digestibility was improved) should be “Previous research showed that a simple mechanical process such as grinding (G) could break up the pericarp and reduce the granular size, partially exposing the endosperm [2], increasing the surface area of the endosperm for rumen enzymes [5], and improving digestibility.”. Furthermore, it would be more suitable to the phrase “two types of thermal processing” instead of “two kinds of thermal processing”.

L111-112 Authors need to give information on how the gas production rate was calculated – which model they used, and whether they used a statistical program.

Figure 2. I fail to see the reasoning to calculate the gas production rate at each time point (there is also a question about how that was calculated). If the authors wanted to show changes within timepoints, it would be more suitable to show the gas production of three processed corn products and calculate one gas production rate of each product for the whole period. It can be estimated using NLIN procedure of SAS package.

L287 Please elaborate on what “And the late fermentation of GC was great” means. Cumulative values of gas production by the end of the fermentation period were high, but it was not high at the late fermentation.

Author Response

Dear Reviewer,

Above all, we’d like to show our appreciation to your suggestions and comments which are very valuable on improving our manuscript. Our response is given in red font and the revised manuscript are marked up using the “Track Changes” function.

The follow is our response to the suggestions and comments.

The quality of the manuscript was improved, but there are several concerns left.

There is still a number of grammar mistakes. For example, the sentence in L36-38 (Previous researches showed that simply mechanical process such as grinding (G) could break the pericarp, reduced the granular size, and endosperm was partially exposed [2], the surface area of rumen enzymes contacted with endosperm is was increased [5] and the digestibility was improved) should be “Previous research showed that a simple mechanical process such as grinding (G) could break up the pericarp and reduce the granular size, partially exposing the endosperm [2], increasing the surface area of the endosperm for rumen enzymes [5], and improving digestibility.”. Furthermore, it would be more suitable to the phrase “two types of thermal processing” instead of “two kinds of thermal processing”. /// Correction was done.

L111-112 Authors need to give information on how the gas production rate was calculated – which model they used, and whether they used a statistical program. Figure 2. I fail to see the reasoning to calculate the gas production rate at each time point (there is also a question about how that was calculated). If the authors wanted to show changes within timepoints, it would be more suitable to show the gas production of three processed corn products and calculate one gas production rate of each product for the whole period. It can be estimated using NLIN procedure of SAS package. ///The model of Orskov and McDonald (1979) was used in the new revised manuscript. Related descriptions were added in the section of materials and methods, results, and discussion. The gas production rate at each time point (it is the average GP rate of two adjacent time periods) in the last manuscript was deleted.

L287 Please elaborate on what “And the late fermentation of GC was great” means. Cumulative values of gas production by the end of the fermentation period were high, but it was not high at the late fermentation.///This sentence was deleted because of the change of calculation method.

Best wishes.

Yanli Guo

 

 

Author Response File: Author Response.pdf